/*
 * linux/arch/ckcore/mm/init.c
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (C) 2006 C-SKY Microsystems co.,ltd.  All rights reserved.
 * Copyright (C) 2006  Li Chunqiang (chunqiang_li@c-sky.com)
 * Copyright (C) 2009  Ye Yun (yun_ye@c-sky.com)
 */
#include <linux/bug.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/pagemap.h>
#include <linux/ptrace.h>
#include <linux/mman.h>
#include <linux/mm.h>
#include <linux/bootmem.h>
#include <linux/highmem.h>
#include <linux/swap.h>
#include <linux/proc_fs.h>
#include <linux/pfn.h>

#include <asm/bootinfo.h>
#include <asm/cachectl.h>
#include <asm/dma.h>
#include <asm/kmap_types.h>
#include <asm/system.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
#include <asm/mmu_context.h>
#include <asm/sections.h>
#include <asm/tlb.h>
#include <asm/virtconvert.h>
#include <asm/ckcore.h>			

DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
unsigned long highstart_pfn, highend_pfn;
unsigned long pgd_current[NR_CPUS];

void pgd_init(unsigned long page)
{
	unsigned long *p = (unsigned long *) page;
	int i;

	for (i = 0; i < USER_PTRS_PER_PGD; i+=8) {
		p[i + 0] = (unsigned long) invalid_pte_table;
		p[i + 1] = (unsigned long) invalid_pte_table;
		p[i + 2] = (unsigned long) invalid_pte_table;
		p[i + 3] = (unsigned long) invalid_pte_table;
		p[i + 4] = (unsigned long) invalid_pte_table;
		p[i + 5] = (unsigned long) invalid_pte_table;
		p[i + 6] = (unsigned long) invalid_pte_table;
		p[i + 7] = (unsigned long) invalid_pte_table;
	}
}

/*
 * We have upto 8 empty zeroed pages so we can map one of the right colour
 * when needed.  This is necessary only on R4000 / R4400 SC and MC versions
 * where we have to avoid VCED / VECI exceptions for good performance at
 * any price.  Since page is never written to after the initialization we
 * don't have to care about aliases on other CPUs.
 */
unsigned long empty_zero_page, zero_page_mask;
EXPORT_SYMBOL_GPL(empty_zero_page);

static inline unsigned long setup_zero_pages(void)
{
	unsigned long order, size;
	struct page *page;

	order = 0;

	empty_zero_page = __get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
	if (!empty_zero_page)
		panic("Oh boy, that early out of memory?");

	page = virt_to_page((void *)empty_zero_page);
        split_page(page, order);
        while (page < virt_to_page((void *)(empty_zero_page + 
                                      (PAGE_SIZE << order)))) 
       {
                SetPageReserved(page);
                page++;
        }

	size = PAGE_SIZE << order;
	zero_page_mask = (size - 1) & PAGE_MASK;
	memset((void *)empty_zero_page, 0, size);

	return 1UL << order;
}

#ifdef CONFIG_HIGHMEM
pte_t *kmap_pte;
pgprot_t kmap_prot;

#define kmap_get_fixmap_pte(vaddr)					\
	pte_offset(pmd_offset(pgd_offset_k(vaddr), (vaddr)), (vaddr))

static void __init kmap_init(void)
{
	unsigned long kmap_vstart;

	/* cache the first kmap pte */
	kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
	kmap_pte = kmap_get_fixmap_pte(kmap_vstart);

	kmap_prot = PAGE_KERNEL;
}

#endif /* CONFIG_HIGHMEM */


/* References to section boundaries */


#ifdef CONFIG_HIGHMEM
static void __init fixrange_init (unsigned long start, unsigned long end,
                                   pgd_t *pgd_base)
{
	pgd_t *pgd;
	pmd_t *pmd;
	pte_t *pte;
	int i, j;
	unsigned long vaddr;

	vaddr = start;
	i = __pgd_offset(vaddr);
	j = __pmd_offset(vaddr);
	pgd = pgd_base + i;

	for ( ; (i < PTRS_PER_PGD) && (vaddr != end); pgd++, i++) {
		pmd = (pmd_t *)pgd;
		for (; (j < PTRS_PER_PMD) && (vaddr != end); pmd++, j++) {
			if (pmd_none(*pmd)) {
				pte = (pte_t *) alloc_bootmem_low_pages(PAGE_SIZE);
				set_pmd(pmd, __pmd(pte));
				if (pte != pte_offset(pmd, 0))
					BUG();
			}
			vaddr += PMD_SIZE;
		}
		j = 0;
	}
}
#endif

void __init pagetable_init(void)
{
#ifdef CONFIG_HIGHMEM
	unsigned long vaddr;
	pgd_t *pgd, *pgd_base;
	pmd_t *pmd;
	pte_t *pte;
#endif
	/* Initialize the entire pgd.  */
	pgd_init((unsigned long)swapper_pg_dir);
	pgd_init((unsigned long)swapper_pg_dir +
	         sizeof(pgd_t ) * USER_PTRS_PER_PGD);

#ifdef CONFIG_HIGHMEM
	pgd_base = swapper_pg_dir;

	/*
	 * Fixed mappings:
	 */
	vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
	fixrange_init(vaddr, 0, pgd_base);

	/*
	 * Permanent kmaps:
	 */
	vaddr = PKMAP_BASE;
	fixrange_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, pgd_base);

	pgd = swapper_pg_dir + __pgd_offset(vaddr);
	pmd = pmd_offset(pgd, vaddr);
	pte = pte_offset(pmd, vaddr);
	pkmap_page_table = pte;
#endif
}

void __init paging_init(void)
{
        unsigned long max_zone_pfns[MAX_NR_ZONES];
        unsigned long lastpfn;

        pagetable_init();

#ifdef CONFIG_HIGHMEM
        kmap_init();
#endif

#ifdef CONFIG_ZONE_DMA
        max_zone_pfns[ZONE_DMA] = MAX_DMA_PFN;
#endif
#ifdef CONFIG_ZONE_DMA32
        max_zone_pfns[ZONE_DMA32] = MAX_DMA32_PFN;
#endif
        max_zone_pfns[ZONE_NORMAL] = max_low_pfn;
        lastpfn = max_low_pfn;
#ifdef CONFIG_HIGHMEM
        max_zone_pfns[ZONE_HIGHMEM] = highend_pfn;
        lastpfn = highend_pfn;

        if (cpu_has_dc_aliases && max_low_pfn != highend_pfn) {
                printk(KERN_WARNING "This processor doesn't support highmem."
                       " %ldk highmem ignored\n",
                       (highend_pfn - max_low_pfn) << (PAGE_SHIFT - 10));
                max_zone_pfns[ZONE_HIGHMEM] = max_low_pfn;
                lastpfn = max_low_pfn;
        }
#endif
        free_area_init_nodes(max_zone_pfns);
}

static inline int page_is_ram(unsigned long pagenr)
{
	int i;

	for (i = 0; i < boot_mem_map.nr_map; i++) {
		unsigned long addr, end;

		if (boot_mem_map.map[i].type != BOOT_MEM_RAM)
			/* not usable memory */
			continue;

		addr = PFN_UP(boot_mem_map.map[i].addr);
		end = PFN_DOWN(boot_mem_map.map[i].addr
			       + boot_mem_map.map[i].size);

		if (pagenr >= addr && pagenr < end)
			return 1;
	}

	return 0;
}

static struct kcore_list kcore_mem, kcore_vmalloc;
#ifdef CONFIG_64BIT
static struct kcore_list kcore_kseg0;
#endif

void __init mem_init(void)
{
        unsigned long codesize, reservedpages, datasize, initsize;
        unsigned long tmp, ram;

#ifdef CONFIG_HIGHMEM
#ifdef CONFIG_DISCONTIGMEM
#error "CONFIG_HIGHMEM and CONFIG_DISCONTIGMEM dont work together yet"
#endif
        max_mapnr = highend_pfn;
#else
        max_mapnr = max_low_pfn;
#endif
        high_memory = (void *) __va(max_low_pfn << PAGE_SHIFT);

        totalram_pages += free_all_bootmem();
        totalram_pages -= setup_zero_pages();   /* Setup zeroed pages.  */

        reservedpages = ram = 0;
        //for (tmp = 0; tmp < max_low_pfn; tmp++)
       for (tmp = min_low_pfn; tmp < max_low_pfn; tmp++)
                if (page_is_ram(tmp)) {
                        ram++;
                        if (PageReserved(pfn_to_page(tmp)))
                                reservedpages++;
                }
       num_physpages = ram;

#ifdef CONFIG_HIGHMEM
        for (tmp = highstart_pfn; tmp < highend_pfn; tmp++) {
                struct page *page = pfn_to_page(tmp);

                if (!page_is_ram(tmp)) {
                        SetPageReserved(page);
                        continue;
                }
                ClearPageReserved(page);
                init_page_count(page);
                __free_page(page);
                totalhigh_pages++;
        }
        totalram_pages += totalhigh_pages;
        num_physpages += totalhigh_pages;
#endif

        codesize =  (unsigned long) &_etext - (unsigned long) &_text;
        datasize =  (unsigned long) &_edata - (unsigned long) &_etext;
        initsize =  (unsigned long) &__init_end - (unsigned long) &__init_begin;

#ifdef CONFIG_64BIT
        if ((unsigned long) &_text > (unsigned long) CKSEG0)
                /* The -4 is a hack so that user tools don't have to handle
                   the overflow.  */
                kclist_add(&kcore_kseg0, (void *) CKSEG0, 0x80000000 - 4);
#endif
        kclist_add(&kcore_mem, __va(0), max_low_pfn << PAGE_SHIFT);
        kclist_add(&kcore_vmalloc, (void *)VMALLOC_START,
                   VMALLOC_END-VMALLOC_START);

        printk(KERN_INFO "Memory: %luk/%luk available (%ldk kernel code, "
               "%ldk reserved, %ldk data, %ldk init, %ldk highmem)\n",
               (unsigned long) nr_free_pages() << (PAGE_SHIFT-10),
               ram << (PAGE_SHIFT-10),
               codesize >> 10,
               reservedpages << (PAGE_SHIFT-10),
               datasize >> 10,
               initsize >> 10,
               (unsigned long) (totalhigh_pages << (PAGE_SHIFT-10)));
}

#ifdef CONFIG_BLK_DEV_INITRD
void free_initrd_mem(unsigned long start, unsigned long end)
{
	if (start < end)
		printk(KERN_INFO "Freeing initrd memory: %ldk freed\n",
                     (end - start) >> 10);

	for (; start < end; start += PAGE_SIZE) {
	ClearPageReserved(virt_to_page(start));
	init_page_count(virt_to_page(start));
	free_page(start);
	totalram_pages++;
    }
}
#endif

extern char __init_begin[], __init_end[];
extern void __init prom_free_prom_memory(void);

void free_initmem(void)
{
	unsigned long addr;


	addr = (unsigned long) &__init_begin;
	while (addr < (unsigned long) &__init_end) {
	        ClearPageReserved(virt_to_page(addr));
	        init_page_count(virt_to_page(addr));
	        free_page(addr);
	        totalram_pages++;
	        addr += PAGE_SIZE;
	}
	printk(KERN_INFO "Freeing unused kernel memory: %dk freed\n",
	        ((unsigned int)&__init_end - (unsigned int)&__init_begin) >> 10);
}
